Lower Mekong basin W18 W18

Threatened HE plains of the lower Mekong still retain some areas of near- Tprimary habitat, with mosaics of open deciduous dipterocarp CR EN VU Total , seasonally inundated wetlands and grasslands, and riverine 42410 habitats. The region supports the entire world population of Giant , together with a high proportion of the global population of ———— White-shouldered Ibis and large numbers of several other threatened —— 11 . The swamp around Tonle Sap, the world’s largest floodplain lake, have the most important waterbird colonies Total 42511 remaining in mainland South-East Asia, with globally significant breeding populations of Spot-billed Pelican, Lesser Adjutant and Key: = breeding in this wetland region. = passage migrant. Greater Adjutant. The seasonally inundated grasslands around the = non-breeding visitor. lake are probably the global stronghold for Bengal Florican, and The Lower Mekong basin region is within grasslands in the Mekong floodplain and delta support several Conservation International’s Indo-Burma Hotspot hundred pairs of Sarus Crane. In addition to the waterbirds, this (see pp.20–21). region has important populations of White-rumped and Slender- billed Vultures (particularly given their rapid declines in South Asia: see G03) and several threatened birds found in forests and associated wetlands (White-winged Duck, Masked Finfoot and Green Peafowl: see F06).

■ Key habitats Freshwater wetlands on riverine plains, seasonally inundated grassland, open deciduous forest, swamp forest. ■ Countries and territories Laos; Cambodia; Vietnam.

The Mekong flood-plain was originally a mosaic of open forest, small seasonal pools and wet grasslands. PHOTO: ELEANOR BRIGGS

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Table 1. Outstanding Important Areas in the lower Mekong basin.

IBA name Status Territory Threatened species 1 Xe Kong plainsF06 (PA) Laos Lesser Adjutant, White-shouldered Ibis, Giant Ibis and Sarus Crane occur in small numbers 2 Dong KhanthungF06 — Laos Large population of Lesser Adjutant, small numbers of Giant Ibis, Sarus Crane and Manchurian Reed-warbler 3 Western Siem PangF06 — Cambodia Lesser Adjutant, White-shouldered Ibis, Giant Ibis, Sarus Crane and White-rumped Vulture 4 ChhepF06 (PA) Cambodia A stronghold for Giant Ibis, also Lesser Adjutant, Greater Adjutant, White-rumped and Slender-billed Vultures, Sarus Crane and Manchurian Reed-warbler 5 LomphatF06 (PA) Cambodia Important for Lesser Adjutant, White-rumped and Slender-billed Vultures and Sarus Crane, also White- shouldered Ibis, Giant Ibis and Greater Adjutant 6 Upper Stung Sen catchmentF06 (PA) Cambodia Breeding Sarus Crane, also Lesser Adjutant, Greater Adjutant, White-shouldered Ibis and Giant Ibis 7 Ang Tropeang Thmor PA Cambodia Non-breeding Sarus Crane, also Spot-billed Pelican, Milky Stork, Lesser Adjutant, Greater Adjutant, White-shouldered Ibis and Bengal Florican 8 Preah Net Preah / Kra Lanh / Pourk — Cambodia Important for Bengal Florican, also Spot-billed Pelican and Sarus Crane 9 Prek ToalF06 PA BR Cambodia Most important site in mainland South-East Asia for breeding large waterbirds, including Spot-billed Pelican, Milky Stork, Lesser Adjutant and Greater Adjutant 10 Stung / Chi Kreng / Kampong Svay — Cambodia Important for Bengal Florican, also Lesser Adjutant, Sarus Crane and Manchurian Reed-warbler 11 Boeung Chhmar / Moat KhlaF06 (PA) BR,R Cambodia Large numbers of Spot-billed Pelican and Greater Adjutant, also Lesser Adjutant 12 Veal Srongae — BR Cambodia Large numbers of Lesser Adjutant, and Bengal Florican, also Greater Adjutant, White-shouldered Ibis and Manchurian Reed-warbler 13 Stung Sen / Santuk / Baray — BR Cambodia Large numbers of Bengal Florican and Manchurian Reed-warbler, also Milky Stork, Lesser Adjutant, Greater Adjutant, White-shouldered Ibis and Sarus Crane 14 Boeung Prek Lapouv — Cambodia Important non-breeding population of Sarus Crane, also Bengal Florican 15 Ha Tien plain — Vietnam Important non-breeding population of Sarus Crane, very small numbers of White-shouldered Ibis and Bengal Florican Some of the waterbirds of this region occur in IBAs listed for region F06, Yok Don NP (Lesser Adjutant, Giant Ibis and White-rumped Vulture) and Cat Tien NP (Lesser Adjutant and White-shouldered Ibis). Note that more IBAs in this region will be included in the Important Bird Areas in Asia, due to be published in early 2004. Key Status: PA = IBA is a protected area; (PA) = IBA partially protected; — = unprotected; BR = IBA is wholly or partially inside Tonle Sap Biosphere Reserve (see pp.34–35); R = IBA is wholly or partially a Ramsar Site (see pp.31–32); F06 = also supports threatened forest birds of region F06.

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OUTSTANDING IBAs FOR extensive areas of open deciduous forest studded with small THREATENED BIRDS (see Table 1) seasonal pools (trapaengs) and seasonally wet meadows W18 (veals), most notably on the plains of northern and eastern This region supports by far the largest waterbird Cambodia, which are the last stronghold for Giant Ibis and populations remaining in South-East Asia, and a total of breeding grounds for White-shouldered Ibis and Sarus fifteen IBAs have been selected, chiefly for their importance Crane. In comparison to the plains of Myanmar (W16) and to Spot-billed Pelican, Lesser Adjutant, Greater Adjutant, Thailand (W17), human population density in most of the White-shouldered Ibis, Giant Ibis, White-rumped Vulture, lower Mekong basin is low, but the region’s wetlands have Slender-billed Vulture and Bengal Florican. nevertheless been subject to professional hunting and seasonal subsistence fishing over a long period, and these CURRENT STATUS OF HABITATS AND pressures are growing. The Mekong and its tributaries THREATENED SPECIES support the only remaining examples of near-intact riverine habitats and bird communities in South-East Asia. The lower Mekong and its major feeder rivers, the Sesan, However, islands in these rivers are used increasingly by Sekong and Srepok, retain the most intact riverine itinerant fishermen and their families for camps, and there is floodplain habitats in the Asia region. There are still regular motorised boat traffic, which may account for the apparent of the Mekong’s Indian Skimmer population. Various proposed hydropower schemes in the The large undeveloped tracts of flood-plain habitats in northern Mekong catchment threaten river flow rates and seasonal and eastern Cambodia are the last stronghold for Giant Ibis. water levels (see below). In Vietnam and parts of southern Cambodia, the Mekong floodplain and delta has been almost totally converted to rice paddy, while much of the remainder is intensively used. Large areas of mangrove and Melaleuca wetlands in the delta were destroyed during the Vietnam War, then replanted, but later cleared for aquaculture. The inundation zone of Tonle Sap lake still has extensive tracts of swamp forest, and grasslands which are subject to a complex and ancient Khmer agricultural ecology. The swamp forests support the only remaining large colonies of communally nesting waterbirds in South-East Asia, and the traditionally managed grasslands have a high proportion of the global population of Bengal Florican.

CONSERVATION ISSUES AND STRATEGIC SOLUTIONS (summarised in Table 3)

Habitat loss and degradation ■ CONVERSION TO AGRICULTURE Wetlands and grasslands in this region are threatened by the PHOTO: ALLAN MICHAUD PHOTO: large-scale intensification of agriculture, in particular the Table 2. Threatened birds of the lower Mekong basin.

Species Distribution and population Spot-billed Pelican Pelecanus philippensis VU Large breeding population in the swamp forest around Tonle Sap lake Milky Stork Mycteria cinerea VU Very small numbers breed in the swamp forest around Tonle Sap lake Lesser Adjutant Leptoptilos javanicus VU Significant numbers breed at Tonle Sap lake, and at lower densities throughout the forested plains Greater Adjutant Leptoptilos dubius EN Significant numbers breed in the swamp forest around Tonle Sap lake White-shouldered Ibis davisoni CR Significant numbers breed in Cambodia; close to extinction in Laos and southern Vietnam Giant Ibis Thaumatibis gigantea CR Entire global population now confined to this region, mainly in northern and eastern Cambodia, but also very small numbers in adjacent parts of Laos and Vietnam White-rumped Vulture Gyps bengalensis ? CR Widely distributed on the plains, in deciduous forest and open habitats Slender-billed Vulture Gyps tenuirostris ? CR Widely distributed on the plains, in deciduous forest and open habitats Sarus Crane Grus antigone VU Several hundred pairs breed in northern Cambodia and southern Laos; outside breeding season moves to north-western and southern Cambodia and the upper Mekong delta in Vietnam Bengal Florican Houbaropsis bengalensis ? EN Significant population around Tonle Sap lake, dispersing to adjacent areas in the wet season; close to extinction in the Mekong delta in Vietnam Manchurian Reed-warbler Acrocephalus tangorum ? VU Recently found wintering in damp grasslands in Cambodia Other threatened waterbirds recorded from this region as rare (or perhaps extinct) visitors are: Black-faced Platalea minor, Pallas’s Fish-eagle Haliaeetus leucoryphus and Indian Skimmer Rynchops albicollis. In addition to the waterbirds, Greater Spotted Eagle Aquila clanga (VU; see F01) and Imperial Eagle A. heliaca (VU; see G01) occur in winter. Note that three species which occur in forests and forested wetlands in the lower Mekong basin, White-winged Duck Cairina scutulata, Masked Finfoot Heliopais personata and Green Peafowl Pavo muticus, are also covered in region F06. = region estimated to support >90% of global breeding population, = 50–90%, = 10–50%; = <10%, ? = proportion of global breeding population unknown; ? = region’s proportion of global non-breeding population unknown

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expansion of irrigated wet rice cultivation. This continuing crops such as pulses, melons, maize and pumpkin. The conversion of seasonally inundated grassland to cultivation spread of agriculture needs to be controlled by setting aside causes loss of natural habitat, falling water levels, land in northern and eastern Cambodia and southern Laos acidification of soils and increased disturbance. Even in the as natural wetlands, involving the establishment of new undeveloped tracts of northern and eastern Cambodia (the protected areas, and by protecting a network of permanent

W18 last hope for species such as Giant Ibis), seasonally flooded pools and seasonal meadows as ‘safe havens’ (see meadows and pools are the first places to be cultivated as Protected areas below). In the inundation zone of Tonle Sap villages gradually spread into unsettled areas. In many lake, the traditional Khmer agricultural ecology should be places, temporary settlements are occupied in the dry promoted and any intensification of rice cultivation must be season along margins of rivers and wetlands, reducing carefully managed, to leave short-grass areas suitable for habitat for large waterbirds. For example, in Kompong breeding Bengal Florican. The remaining seasonally Thom province in Cambodia around 30% of wetlands inundated grasslands in the Mekong Delta regions of were thought to be seasonally settled by people who plant Cambodia and Vietnam are extremely important for Sarus Crane and other waterbirds, and should be protected from

Tibetan plateau Tibetan conversion. Protected areas have been established at some key wetlands for threatened birds in Cambodia. ■ CONFLICT WITH FISHERIES The conservation of Tonle Sap lake and the surrounding wetlands involves several complex issues, the entire area being a private fishing concession leased piecemeal to fishing businesses and cooperatives. Annual profits from fishing in ‘Lot 2’ alone (the area that contains the bulk of the waterbird colonies) run into hundreds of thousands of US dollars, and conservation interests have little chance of competing against such an important economic activity. Negotiations are needed to resolve current and potential conflicts between fishermen and conservationists, with the aim of continuing to manage the whole area as a low- impact fishery (which would maintain fish stocks and benefit wildlife), with conservation management in the areas PHOTO: ELEANOR BRIGGS PHOTO: around waterbird breeding and feeding sites. Table 3. Conservation issues and strategic solutions for birds of the lower Mekong basin.

Conservation issues Strategic solutions Habitat loss and degradation ■ CONVERSION TO AGRICULTURE ➤ Promote the traditional Khmer agricultural ecology around Tonle Sap lake ■ CONFLICT WITH FISHERIES ➤ Manage any intensification of rice cultivation in the inundation zone of Tonle Sap lake to leave short-grass ■ CUTTING OF NESTING areas for breeding Bengal Floricans ■ DEVELOPMENT (URBAN, INDUSTRIAL, ETC.) ➤ Prevent any further conversion of seasonally inundated grasslands in the Mekong Delta ■ REDUCED FOOD SUPPLY (FOR VULTURES) ➤ Continue to manage Tonle Sap as a low-impact fishery, to maintain fish stocks and protect threatened birds ■ DISTURBANCE ➤ Manage the forests at Tonle Sap and other wetlands sustainably, and maintain patches of old growth to ■ POLLUTION provide nesting habitat for waterbirds ➤ Critically review all dam projects in the Mekong watershed, to minimise their impact on ecological processes and the region’s biodiversity ➤ Assess the environmental impact of development projects, with mitigation if they damage wetland habitats ➤ Maintain and restore vulture food supplies from traditional extensive livestock management, with supplementary feeding if required ➤ Introduce community conservation programmes to reduce disturbance in the inundation zone of Tonle Sap lake ➤ Ban the use of chemicals or dynamite for fishing ➤ Control the use of pesticides and herbicides, especially near key wetlands Protected areas coverage and management ■ GAPS IN PROTECTED AREAS SYSTEM ➤ Establish new wetland protected areas, including ‘safe havens’ to prevent human disturbance at key waterbird ■ WEAKNESSES IN RESERVE MANAGEMENT sites in southern Laos and Cambodia ➤ Define and establish protected areas at Tonle Sap, seeking compromise between its management as a fishery and as a sanctuary for wildlife ➤ Develop zonation of large protected areas to minimise conflicts between biodiversity conservation and human usage ➤ Resolve problems with protected area legislation in Laos and Cambodia ➤ Strengthen reserve management through improved funding, infrastructure and staff training Exploitation of birds ■ HUNTING ➤ Improve, publicise and enforce hunting laws, including through monitoring trade in threatened waterbirds at ■ EGG AND CHICK COLLECTION Cambodian food-stalls ➤ Control gun ownership, particularly near important wetlands ➤ Continue and expand the programme to control the exploitation of eggs and nestlings at Tonle Sap waterbird colonies Gaps in knowledge ■ INADEQUATE DATA ON THREATENED BIRDS ➤ Survey White-shouldered Ibis, Giant Ibis and other large waterbirds in northern and eastern Cambodia ➤ Identify key non-breeding areas for Bengal Florican, and investigate the role of agricultural practices in maintaining its breeding habitat around Tonle Sap lake ➤ Study the ecology and monitor populations of threatened waterbirds, to help improve management of protected areas

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that many fewer livestock carcasses are left for the vultures). There are several large waterbird colonies in the swamp Supplementary feeding could be considered as a short-term W18 forests around Tonle Sap lake, but many eggs and chicks are measure to help the remaining vulture populations, but taken by professional collectors. ultimately food supplies need to be restored through localised changes back to traditional livestock management, and ideally the protection and recovery of large ungulate populations.

■ DISTURBANCE Throughout the Mekong basin human populations are gradually spreading along the rivers into the most remote regions. Local people consume large quantities of fish and other aquatic products, so most wetlands are badly affected by (e.g.) new or seasonal settlements (with ubiquitous dogs), buffalo grazing and trampling, and hunters and fishermen. Waterbirds are very wary of hunters, and easily flushed from their foraging sites or nests. A network of ‘safe havens’ (see Protected areas below) is required for large waterbirds, a scheme involving the exclusion of human activity around important nesting, foraging and roosting sites for storks, and cranes (both within and outside protected areas), particularly in the dry season when habitat availability is

PHOTO: ELEANOR BRIGGS PHOTO: most limited and birds most vulnerable to disturbance and hunting. As local people require wetlands for various ■ CUTTING OF NESTING TREES purposes, zoning is needed, with a few important wetlands In many parts of Asia large waterbirds have lost potential classed as strict no-entry zones for a few months during the breeding habitat through the felling of tall trees near dry season. This idea should be expanded to cover as many wetlands. The swamp forests around Tonle Sap lake still sites as possible in northern and eastern Cambodia and provide habitat for several large colonies, although large southern Laos, although enforcement in remote regions will tracts have apparently already been logged or converted to be very difficult. Community conservation programmes agriculture; forest clearance is currently proceeding at a slow could be introduced in the inundation zone of Tonle Sap rate there, but the pressure to exploit the remainder is likely lake, under which Bengal Florican nests would be marked to intensify as timber resources become depleted elsewhere. to avoid accidental disturbance. In the Mekong delta’s Melaleuca swamp forests, forest fires are a constant risk owing to excessive use of ground-water, ■ POLLUTION which is lowering the water table and drying out the Levels of agricultural or industrial pollution are currently underlying peat. The forests around Tonle Sap and other relatively low, although some waterways are deliberately important wetlands need to be managed sustainably, with poisoned or dynamited to kill fish for eating: this destroys patches of old growth maintained near wetlands to provide much aquatic fauna including birds. Large waterbirds and sites for waterbird colonies. raptors are usually predators or scavengers, and thus vulnerable to build-up of toxic chemicals in the food chain. ■ DEVELOPMENT (URBAN, INDUSTRIAL, ETC.) The use of chemicals or dynamite to kill fish should be Various hydropower projects are proposed in the Mekong banned. Existing and new laws should be enforced in all catchment, especially in Yunnan, Laos and Vietnam, and countries to control the use of pesticides (such as dieldrin threaten its ecological balance. This is a particular threat to and aldrin) and herbicides, especially near important wetlands. the Mekong’s highly diverse (and often migratory) fish fauna that is so important as food for waterbirds and people. Near Protected areas coverage and management towns, waterbird foraging areas are being lost to increasing ■ GAPS IN PROTECTED AREAS SYSTEM urban and industrial development. This places a demand on Some of the most important wetlands in the lower Mekong timber, which is collected from swamp forests and mangroves basin are officially protected, but several new protected for domestic use and construction. Grasslands and wetlands areas should be established, including Dong Khantung in at the Ang Tropeang Thmor Reserve are threatened by plans Laos. In Vietnam, a nature reserve is needed for key habitats to develop a village. Proposals to dam the Mekong and its in the Ha Tien Plain, possibly established under national tributaries should be critically reviewed, to minimise damage protected areas legislation, or a private reserve involving the to ecological processes and globally outstanding corporate sector. In Cambodia, a national conservation biodiversity; some individual projects may cause extreme area should be established at Boeung Prek Lapouv, and in ecological disruption, and their cancellation may be western Siem Pang district a system of small seasonally appropriate. Detailed environmental impact assessments closed sites, or ‘safe havens’, might be developed to prevent should be mandatory for development proposals, and human activity around important nesting, foraging and appropriate mitigation enforced (e.g. re-creation of habitats). roosting sites for storks, ibises and cranes. If successful, this model should be extended to elsewhere in northern and ■ REDUCED FOOD SUPPLY (FOR VULTURES) eastern Cambodia, and southern Laos. Alternatively, if A key factor in vulture declines in South-East Asia appears government support were forthcoming, it may be more to be the collapse in food supply, as a result of crashes of appropriate to extend protected area status to part of large ungulate populations and a transition from extensive western Siem Pang district. The protected status of key to intensive livestock management in many areas (meaning waterbird sites at Tonle Sap lake needs to be more clearly

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defined, with the aim of finding a compromise between its monitoring of their activities; (3) a blanket ban on management as a fishery and as a sanctuary for wildlife (see collection in designated core areas, these encompassing all Conflict with fisheries above). Further core areas should be or part of colonies; (4) guarding of lakeward and landward designated within Tonle Sap Biosphere Reserve, to improve access to colonies to prevent smuggling of eggs and chicks; coverage of the swamp forest, including the remaining (5) development of alternative livelihoods for professional

W18 unprotected large waterbird colonies, and the seasonally egg and chick collectors. Conservation awareness inundated grasslands. programmes are also required, targeted at officials, local people and schools around Tonle Sap, to emphasise the ■ WEAKNESSES IN RESERVE MANAGEMENT importance of protecting wetlands and large waterbirds, Many gazetted and proposed protected areas are large, for and old and new laws relating to activities at waterbird example many National Protected Areas in Laos, and colonies. In the Upper Stung Sen catchment, a pilot Site require careful zonation to minimise conflicts between long- Support Group (see p.21) has been established, which term conservation and legitimate human uses. Throughout involves local stakeholders in the protection of nesting the region, there are problems with the current protected waterbirds; this could be a model for many other areas.

Tibetan plateau Tibetan areas legislation, as well as inadequate funding, equipment and manpower. A re-evaluation and redefinition of legal Gaps in knowledge terms is therefore required, particularly those applying to ■ INADEQUATE DATA ON THREATENED BIRDS protected sites and species in Laos and Cambodia, and Further surveys are needed to clarify the distribution, increased funding and training is needed to strengthen seasonal movements and ecology of large waterbirds and governmental conservation and forestry departments. vultures in Cambodia, particularly White-shouldered Ibis and Giant Ibis, and to identify the most important sites for Exploitation of birds their conservation. Further research is also required to ■ HUNTING identify key non-breeding sites for Bengal Florican, and to Hunting is a widespread practice for many cultural and investigate whether existing agricultural systems help in economic reasons in Indochina. Wildlife is seen as a maintaining suitable breeding habitat. The establishment of culinary delicacy and income earner, and populations of all new protected areas, and the improved management of large species of open habitats have declined as a result. existing reserves, requires research to determine the most Waterbirds are poisoned, shot, or caught on hooked lines. appropriate boundaries and management regimes. For Until the recent establishment of a conservation area, the example, the measures required to maintain waterbird Sarus Cranes at Ang Tropeang Thmor were hunted for numbers at Prek Toal includes the following research food, or captured for trade to Thailand. In the dry season, elements: (1) evaluation and monitoring of threats (e.g. the problem intensifies as permanent wetlands attract conversion of forest to farmland, exploitation of concentrations of waterbirds that are especially susceptible waterbirds) from nearby communities; (2) annual to intense hunting pressure. Laws need to be strengthened in monitoring of waterbird numbers and levels of all countries, and then well publicised (including the exploitation, with efforts to assess the impact on their environmental justification for this legislation) and populations and to evaluate the potential for sustainable enforced, especially at important wetlands. However, Laos, management; (3) continued aerial surveys of the Prek Toal Cambodia and Vietnam have policies and active area to locate colonies and estimate waterbird populations; programmes to control gun ownership, and these may be a (4) research into the viability of alternative livelihoods and more effective and immediate way of reducing hunting ecotourism. pressure than legislation or new protected areas. This gun control should be continued in southern Laos and Vietnam, and if possible also implemented in northern Cambodia, particularly near key wetlands. Enforcement officials should Surveys are needed to clarify the distribution, seasonal routinely visit food stalls and markets throughout the region movements and ecology of White-shouldered Ibis and other to monitor bird trade, confiscate endangered species and large waterbirds in Cambodia. fine offenders.

■ EGG AND CHICK COLLECTION Professional collectors work the waterbird colonies at Tonle Sap, taking many thousands of clutches of eggs and chicks from pelican and stork nests each year. Many of the young birds are reared and fattened before sale, often to middlemen who sell them for food in Battambang and Siem Reap. Surveillance by Wildlife Protection Office staff was thought to have improved the situation, but recent news indicates that the colonies are still poached from their unguarded landward sides. In northern Cambodia and southern Laos, the eggs and chicks of the ground-nesting Sarus Crane are easily accessible, and are taken annually from known nesting sites for food or sale. An ongoing long-term conservation programme at Tonle Sap needs to be continued and expanded, involving the following components: (1) permanent presence of Wildlife Protection Office staff during the breeding season at

colonies; (2) registration of egg and chick collectors and PETE MORRIS/BIRDQUEST PHOTO:

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